Hospitals are without stocks of essential drugs and pharmaceuticals. Power generators are used sparingly to eke out what low fuel supplies are left. Medical equipment parts are unavailable to repair or replace ageing tools and instruments. And only the most essential operations are being carried out.

Shifa hospital was forced to suspend all elective surgical operations for several days in late October after running out of the anesthetic nitrous oxide.

Only after urgent intervention by the U.N. Office for the Coordination of Humanitarian Affairs and the World Health Organization with Israeli permission, gas was recently delivered through Gaza's southern Kerem Shalom crossing.

However, Dr. Bassem Naem, Hamas' minister of health told the Middle East Times that their effort to get sufficient quantities of nitrous oxide and other essential medicines, which are supplied by the Israeli medical company Maxima, was an ongoing one.

"We have to make continual appeals through human rights organizations, and only when the situation reaches critical levels do the Israelis allow minimum amounts of gas and medicines through," he said.

But Shadi Yassin, a spokesman for the Israeli Defense Forces told the Middle East Times, "The Israeli military does not prevent essential medicines from going into Gaza.

"As long as there is relevant coordination through organizations such as the WHO, medicine gets through. We received only 24-hours notice to the October shortage of nitrous oxide, and once informed we arranged immediate delivery."

Nevertheless, Ran Yaron, a humanitarian coordinator from Israel's Physicians for Human Rights said, "The situation in Gaza is critical."

"Gaza's hospitals have run out of nearly 140 essential medicines and are running low on another 90. So desperate is the situation that we have launched an international appeal for funds and medicines and are in the process of coordinating an emergency delegation of doctors to Shifa Hospital to deliver medicine and money," he said.

Other Palestinian health ministry hospitals are carrying out only the most urgent operations, using alternative anesthetics to nitrous oxide as supplies become depleted. Gaza's main pediatric hospital has reported running critically low on fuel for its generator on which hospital machinery is dependent. The fuel shortage has also forced hospitals to cut back on their use of ambulances.

More and more equipment, such as kidney dialysis machines and incubators, have stopped functioning altogether, because hospitals can't get fuel and spare parts from outside Gaza.

Israel is refusing to allow donated machines into the Gaza Strip.

"The Israelis say that importing medical equipment and parts for these machines does not fall within the humanitarian aid category," Naem said.

Israel has slowly tightened an economic siege it imposed on Gaza after the Hamas government took power there in June.

The number of U.N. and other humanitarian trucks carrying essential food aid, such as flour, rice, oil, and beans, has been restricted and a number of crossings from Israel into Gaza closed.

Consequently, supplies of fresh fruit and vegetables, dairy, and meat products have dwindled and are adding to an already serious malnutrition problem.

Additionally, Israel has responded to continued Qassam rocket attacks on Israel by Gaza militants by reducing supplies of diesel since October by 49 percent, petrol by 40 percent, and industrial diesel by 14 percent according to the World Health Organization.

But the Petroleum and Gas Station Owners' Association of Gaza says commercial fuel supplies were cut by more than that: from 350,000 to 180,000 liters of diesel and 120,000 to 45,000 of petrol daily.

Electricity in Gaza is already in short supply and frequent power cuts are a daily occurrence. Israeli has threatened to cutting electricity to Gaza still further as a punitive measure against militant attacks.

According to a recent Humanitarian Monitor report released by the U.N.'s Office for the Coordination of Humanitarian Affairs, if electricity cuts build up to 20 hours per week the dependence on fuel in hospitals and health facilities will be increased to some 150,000 liters per month. Currently there is an average electricity cut of four to six hours a week in Gaza with an average monthly consumption of fuel in government health facilities of 85,200 liters a month.

"If further sanctions are implemented, the provision of immunization, diagnostic, and dental services and the sterilization of tools needed for dressings will be affected in Palestinian Health Center facilities.

Diagnostic services including intensive care unit equipment, laboratory and x-ray, operating rooms, oxygen extractors, laundry rooms, air conditioning system, and water pumps will also be affected at hospitals' level," the report stated.

Aggravating the medical crisis is the increasing number of chronically ill Gazans who are not permitted by Israel to travel to or through Israel for further medical treatment either in Israel or neighboring countries on the grounds they pose a security threat.

According to Palestinian health ministry and WHO records, 44 people have died since June because the Israeli authorities denied or delayed medical care access to them. Thirteen died in November alone and the number is expected to rise as Israel's siege policy tightens.